1. Field of the Invention
The present invention is related to an apparatus for preventing ice from forming on vehicle windshield wiper blades and wiper blade assemblies even during very cold weather. More particularly, the present invention is directed to an electrically heated housing or cover that is easy to install or remove from a windshield wiper and wiper blade assembly that prevents formation of ice on the wiper blade and wiper blade assembly during snow storms, ice storms, freezing rain storms and the like.
2. Description of Related Art Including Information Disclosed Under 37 C.F.R. Sections 1.97-1.99
In very cold weather, it may be difficult or impossible to prevent build-up of ice on vehicle windshield wiper blades, wiper blade assemblies and the windshield, even with the vehicle engine fully heated and properly operating defrosters working as effectively as possible. The build-up of ice on the windshield, wiper blades and the wiper blade assemblies is naturally a grave safety hazard, requiring drivers to stop periodically along the road, sometimes as often as every 10-15 minutes, to scrap the ice from the wiper blade assemblies and the windshield. This procedure itself is very hazardous because it is frequently not possible to leave the road entirely and visibility of all drivers is usually very limited during weather conditions that lead to formation of heavy ice on the windshield.
Truck drivers, who must drive through mountains and in all weather, perhaps face this problem most starkly. Truck drivers experience the greatest difficulty in finding a safe place to stop their trucks to clear the windshield and wiper blade assemblies of ice. Trucks must allow greater distances for stopping, especially during inclement weather and for maneuvering, so reduced visibility places them in even greater danger than passenger cars and busses.
In the past many efforts to address and solve this problem by directly heating the wiper blade or its immediate environment outside the vehicle (as opposed to an interior defroster or electrically heated windshield with resistance elements such as wired embedded therein) have been made, and some have led to issued patents. Most of these solutions involve efforts to heat the wiper blade itself, typically by running an electrical heating element though the rubber or rubber-like wiper blade. These types of solutions have not become widely adopted because they share numerous problems. For example, the flexible edge of typical windshield wiper blades are too narrow to allow the passage of all but the smallest heating element, one which could not carry enough heat to keep the wipers and windshield free from ice. A small heating element in the wiper blade itself, moreover, will not prevent the formation of ice on the wiper blade assembly, which permits the wiper blade assembly to flex and bend, as it must in order to allow the wiper blade to follow the curvature found on most windshields and to press the wiper blade firmly against the windshield. This causes the wiper blades to skate across the windshield, with significant portions of the blades not in contact with the windshield. Placing a heating element wire through the wiper blade causes the blade to lose some of its flexibility, which is vital to its function because the edge of the blade bends to change its angle of attack relative to the windshield every time the wiper blade assembly changes direction of motion. Heat and ozone are probably the two factors that cause the most severe damage to wiper blades, which typically loose their effectiveness after only a few months at most under good conditions. Heating them significantly and deliberately causes failure much faster. Further, it is relatively expensive to provide a heating element through a wiper blade. The wiper blades would be on the vehicle all the time, but their ice prevention capability would rarely be needed. These expensive blades either would be used as ordinary blades for the overwhelming proportion of their lives, or the vehicle operator would install them only when needed. But when the apparent need for them becomes evident, the weather will likely make their installation either very difficult or impossible. For these and other reasons, electrically heated wiper blades themselves, i.e., having a heating element embedded in the wiper blade, are not adequate solutions to the problem.
Another approach to solving this problem was to provide a wiper blade assembly including a single rod of electrically resistive metal along the assembly in a single unitary unit that cannot be repaired. Such assemblies have are very expensive to make compared with wiper blades and have no provision for changing the wiper blades, requiring wasteful disposal of the entire unit whenever the wiper blade wears out. Further, such units are too heavy for the power of most windshield wiper motors, causing them to burn out prematurely.
Therefore, it is clear that there is a need for a removable heated cover for vehicle windshield wiper blades that can be readily installed and removed; that does not require any change in the wiper blade or wiper blade assembly; that does not distort or otherwise alter the normal action of the wiper blade; that is light weight, thereby not overtaxing wiper motors; that prevents formation of ice on wiper blades, wiper blade assemblies and the windshield; and that is inexpensive to manufacture; and that can be readily stored with other emergency supplies such as flares, triangular reflectors, jumper cables and the like, for use during heavy icing conditions.